Inside a helium nucleus: mapping quarks and gluons in 3D

Elastic scattering and Compton scattering experiments on helium-4 can reveal the internal quark-gluon structure with unprecedented precision by exploiting quantum chromodynamics factorization. The team computed generalized parton distributions at next-to-leading order with full evolution, exposing how quarks and gluons occupy different transverse regions inside the nucleus. This is the first direct 3D tomography of any light nucleus and could anchor new tests of QCD in the nuclear regime.